If you are reading this, it is likely that you are interested in genealogy and family history, and that means that you have visited more than your fair share of graveyards.
Graveyards are a wonderful place to find information that is not otherwise easily discovered. If the person you are looking for died less than 75 years ago (at least in Ontario) you can ususally find a date of death, which in turn can lead to the obituary/death notice in the local paper, which can lead to the names of other family members, in-laws, etc. Often you will find family plots with the children, grandparents, aunts, uncles, and other in-laws all buried in close proximity.
Even information that is not there can be of assistance. Consider a headstone that has birth and death dates of the husband on it, but not that of the wife, or only the birth date of the wife, but not a death date, even if the wife must clearly be dead by now.
The assistance one can get at a graveyard varies wildly. Many rural cemeteries have no office, and the boards are not easy to contact. Cemeteries that are defunct or abandoned, whether rural or urban, almost never have assistance of any description. In the case of Ontario you can use the OCFA, or the OGS Ontario Cemetery Ancestor Search, but they do not cover every cemetery in the province, and rely on volunteers to transcribe microfilms of old records, which brings in a whole new area for errors to be made. The best bet for rural cemeteries is to simply wander among the gravestones until you find what you are looking for.
Urban cemeteries usually have offices, but the quality and hours of service vary wildly. I know of one group of cemeteries in Toronto where the operating company has decided that none of the offices will be open on weekends. Their records are also completely paper based. They are a 9 to 5 operation. The staff are not exactly the friendliest people in the world either. All in all my dealings with them have had a slight air of the surreal. Contrast that to another major cemetery group in Toronto where the records are computerized, the staff are friendly and helpful, and they have office hours at their sites on the weekends.
Many cemeteries, especially in rural areas, but also some in the cities, are in very bad condition. Headstones toppled through vandalism or neglect, botched restorations of headstones (Never, ever use iron/steel pins to put a headstone together again), encroaching vegetation. Old marble headstones are especially vulnerable to the elements and mistreatment.
If you do visit cemeteries, take pictures of the headstones, and then share them. There are many sites that allow you to upload or submit headstone photos: the CanadaGenWeb Cemetery Project, FindaGrave, Northern Ontario Canada Gravemarker Gallery, and the Gravestone Photographic Resource Project.
In the end, graveyards are both a source of joy and sadness for both family members, and for genealogists. Joy for finding the relationships, dates, and relatives you never knew, and sadness in the realization that someday we will all be there, with only a stone to mark our place, and sometimes not even that.